How can I differentiate duration vs starting time

Let’s say I have a meeting at 06:00 AM that is scheduled to last 8 hours and 15 mins . Are there any guidelines, tips or tricks to display that information in a non-ambiguous way?

If I simply display in the agenda:

06:00 - Meeting (08:15)

It can easily be misunderstood as 8:15 being either the end if meeting or, even worse, ( since we are using multiple timezones in my app) a different time zone time.

The example is obviously made up, in the real app I have a lot of starting times and a lot of durations to express in a relatively small amount of space on the same page. Simply converting to text (8 hours and 15 minutes) is not an option as it will not fit. I have space for maybe max 10 chars per item.

So how so you display a timespan in a way that is different from a datetime?

Later edit: and just to make the question harder. How about expressing time-to-go, as in the meeting is in 2 hours and 53 minutes. I need an accurate display, and most timers/chrono applications that use countdowns (eg. phone alarm apps) infuriatingly use the same 00:00 display for duration